Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore has been drilled, the well must be completed before hydrocarbons can be produced from the well. A completion involves the design, selection, and installation of equipment and materials in or around the wellbore for conveying, pumping, or controlling the production or injection of fluids. After the well has been completed, production of oil and gas can begin.
Sand or silt flowing into the wellbore from unconsolidated formations can lead to an accumulation of fill within the wellbore, reduced production rates and damage to subsurface production equipment. Migrating sand has the possibility of packing off around the subsurface production equipment, or may enter the production tubing and become carried into the production equipment. Due to its highly abrasive nature, sand contained within production streams can result in the erosion of tubing, flow lines, valves and processing equipment. The problems caused by sand production can significantly increase operational and maintenance expenses and can lead to a total loss of the well.
One means of controlling sand production is the placement of relatively large grain sand (i.e., “gravel”) around the exterior of a slotted, perforated, or other type liner or sand screen. The gravel serves as a filter to help assure that formation fines and sand do not migrate with the produced fluids into the wellbore. In a typical gravel pack completion, a sand screen is placed in the wellbore and positioned within the unconsolidated formation that is to be completed for production. The sand screen is typically connected to a tool that includes a production packer and a cross-over, and the tool is in turn connected to a work or production tubing string. The gravel is mixed with a carrier fluid and pumped in slurry form down the tubing and through the crossover, thereby flowing into the annulus between the sand screen and the wellbore. The carrier fluid in the slurry leaks off into the formation and/or through the sand screen. The sand screen is designed to prevent the gravel in the slurry (and other contaminates such as sand and silt) from flowing through it and entering into the production tubing. As a result, the gravel is deposited in the annulus around the sand screen where it forms a gravel pack. It is important to size the gravel for proper containment of the formation sand, and the sand screen must be designed in a manner to prevent the flow of the gravel through the sand screen.
Sand screen types may include wire-wrapped and wire-mesh screen. A wire-wrapped screen generally includes a relatively fine wire wrapped and spot welded to an underlying tubular with interstitial spaces between adjacent wires, whereby the interstitial spaces are sized to prevent particles of a predetermined size from passing through the wire-wrapped screen. Examples of wire wrapping techniques are disclosed in U.S. Pat. No. 3,275,785 and U.S. Pat. No. 4,314,129, which are both incorporated herein by reference. The screen generally circumscribes a length of perforated pipe known as a base pipe. Accordingly, a hydrocarbon fluid (e.g., oil) is permitted flows through the wire-mesh screen and a percentage of particulate matter is filtered from passing through. The perforations along the side of the base pipe allow the fluid to enter into a production tubing. In other sand screen embodiments, the screen circumscribes a solid base pipe having an inflow control device for regulating the inflow of fluids into the base pipe.
The present invention includes various embodiments of tools, systems, and processes for the manufacturing of such sand screens.